To sign up for "kindle Unlimited", go to
www.amazon.com/kindleunlimited.
It offers "Unlimited listening, Unlimited reading on any device you have",
such as your smart phones, Kindle readers, or your PC or Apple.
You do not have to buy Kindle Reader.

To do that, you download "Kindle Installer" from
http://kindleforpc.amazon.com/42052/KindleForPC-installer-1.13.42052.exe
for your PC, or download "Kindle Application" from your smart phones.

They give you 30-day free trial, and after that, it is $9.99 per month.

Of course, you can download and read (or listen) Dream Wafer
as well as many thousands of books for free during the trial period.

I do not know actual details because I have not tried personally myself
but the above is what I learned.